The cooperation-game between a company and farmer is studied under the multi-farmer competition in a two-stage supply chain of perishable products

consisting of multi-farmers and a company.Based on grey-system theory

the cooperation and the violation between a company and farmers is analyzed by setting up the grey-game model.The analysis indicates that the setting of the penalty for the company breaking a contract and the rewarding for farmers keeping it is the main factor that decides whether or not they cooperate;and that competition among farmers only has influence on the farmers rather than the company violating a contract and does not have influence on the the company when market price is lower than contract price.Finally

the strategy and means

which realize the united optimization to reach Nash equilibrium in the supply chain system of perishable products

are presented and demonstrated by examples.